Oliver had a thing for rocks, in fact he would put anything in his mouth. He thought it was a big game too. He loved it when we would chase him. I don't know if he ate any but I do know he ate a sock, he did puke it up. After that we had him xrayed and an ultrasound to make sure there wasn't anything else in there. We had everything removed and EasyTurf installed and that put a stop to the rock eating. I would suggest the training method others have done to stop the rock eating, it's alot cheaper too.